1. Field of the Invention
The invention relates to an electric switch, in particular a piezo switch, with optical and/or mechanical feedback of the switching operation. The invention is expressly, but not exclusively, related to piezo switches, but all functional principles of an electric switch are to be covered by the invention and consequently will be protected. In the following paragraphs, reference is only made to the preferred application of a piezo switch.
2. Description of the Prior Art
Such a piezo switch is disclosed for example in the subject matter of U.S. Pat. No. 4,430,595, in which in an approximately cubical housing a piezo element is disposed, which is actuated from above by an actuator, which with its actuation face extends through a cutout in a formed cover part. As the actuation face is provided a round, relatively flat face and the entire actuator is not illuminated.
DE 197 04 253 A1 disclosed an operating unit for motor vehicle components with a movable operating element, at whose front wall section an at least partially translucent symbol field is disposed, and a light guide element is disposed under the front wall section of the operating element which acts onto a switching member of the switch for the purpose of its actuation if the operating element is moved downwardly. The symbol field is directly illuminated by a light element via the light guide element, with the light element being disposed beneath the light guide element. The light guide element has an oblique surface for the incidence of light, which permits the off-center position of the light element due to the central position of the switch.
Of disadvantage herein is that for the actuation of the switch several different elements expensive of production and at least partially transparent (operating element with symbol field and light guide element with oblique surface) must be provided, which leads to increased material and assembly costs as well as also to a lower light yield through light absorption, in particular at the transitions of the different elements. An optical and/or mechanical feedback for the switching operation is not disclosed in DE 197 04 253 A1.
The invention is based on the task of developing further a switch, in particular a piezoelectric switch, of the above described type such that an optical and/or mechanical feedback of the switching operation takes place in an especially noticeable manner.
An essential characteristic of the invention is that the actuation element itself is developed as a passive luminous body of an at least translucent material, with the passive luminous body being illuminated via active illuminating means.
With the provided technical teaching the significant advantage is obtained that now the actuator of the in particular piezoelectric switch overall is formed as a luminous body, which is preferably comprised of a translucent synthetic material.
Such a synthetic material should thus be developed at least as a partially translucent material, but it can also be formed to be completely transparent.
This can involve here a single-layer or a multi-layer luminous body, such that with its back side illumination, the light overall is uniformly distributed in the luminous body developed as an actuator.
If the actuation surface (i.e. the face of the switch close to the user and to be pressed) is developed as a symbol field, the symbol body is especially intensely luminous. An especially impressive luminous phenomenon is obtained if the symbol body is three-dimensionally milled out of the front face of the luminous body, such that it is only necessary to press the symbol body in order to actuate the luminous body developed as an actuator, which, in turn, actuates the switching element in the switch.
This yields for the first time the advantage that no actuation housing for a luminous body is necessary, as is for example taught in DE 31 33 134 A1.
In it, the precondition is that in an approximately bulb-form opaque housing at the front side a translucent synthetic pane is inserted, which is back-illuminated by one or several LEDs.
This necessitates a structure requiring extensive space and yields an unimpressive illumination of the actuation face since the actuation face is relatively small.